// Copyright 2013 Beego Samples authors
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.

package models

import (
	"container/list"
)

type EventType int

//事件类型常数
const (
	EVENT_JOIN     = "EVENT_JOIN"     //事件类型建立连接
	EVENT_LEAVE    = "EVENT_LEAVE"    //事件类型断开连接
	EVENT_MESSAGE  = "EVENT_MESSAGE"  //事件类型消息
	WELCOM_MESSAGE = "WELCOM_MESSAGE" //事件类型消息欢迎词
)

//事件结构
type Event struct {
	Type        string        `json:"cmd"` //类型 JOIN, LEAVE, MESSAGE
	UserName    string        `json:"username,omitempty"`
	UserId      int64         `json:"userid,omitempty"`
	TargetId    string        `json:"targetid,omitempty"`
	RoomId      string        `json:"roomid,omitempty"`
	TimeStamp   int           `json:"timestamp,omitempty"` // Unix timestamp (secs)
	Content     string        `json:"msg,omitempty"`
	OnlineUsers []interface{} `json:"onlineUsers,omitempty"`
}

const archiveSize = 20

//事件档案。
var archive = list.New()

// NewArchive将新事件保存到归档列表。
func NewArchive(event Event) {
	if archive.Len() >= archiveSize {
		archive.Remove(archive.Front())
	}
	archive.PushBack(event)
}

// GetEvents返回lastReceived之后的所有事件。
func GetEvents(lastReceived int) []Event {
	events := make([]Event, 0, archive.Len())
	for event := archive.Front(); event != nil; event = event.Next() {
		e := event.Value.(Event)
		if e.TimeStamp > int(lastReceived) {
			events = append(events, e)
		}
	}
	return events
}
